Ptolus is based upon the setting for Cook's home game, which served as the initial campaign for the 3rd edition of Dungeons and Dragons. The campaign centers around the city of the same name, which lies on the Whitewind Sea at the edges of the crumbling empire of Tarsis. The city lies in the shadow of an impossibly tall and narrow spire. Below the city are many dungeons, including the city's sewers and a forgotten dwarven city named Dwarvenhearth.

The book's author claims it is the "most deluxe roleplaying product ever published," weighing in at 672 pages with multiple special features, including a CD-ROM that includes a new adventure, The Night of Dissolution, and two previous Malhavoc products with Ptolus connections: The Banewarrens and Chaositech. The book was produced in hardback on full colour glossy paper. The first 1000 pre-publication orders of the Ptolus book had their copy signed and numbered by Monte Cook. All pre-ordered copies also received a printed copy of The Night of Dissolution, which was not otherwise available at the time, and five copies of A Player's Guide to Ptolus.

A Player's Guide to Ptolus consists of the material of Chapter 1 of Ptolus. It was available for separate sale from several months before Ptolus either individually or in packs of five. As well as five copies coming free with pre-orders of Ptolus, it is also available in PDF format on CD that comes with all printed copies of the Ptolus book and available for free download. The contents of this book is designed to represent the common knowledge available to city residents or visitors to Ptolus. It is intended that each player in a Ptolus campaign should have access to a copy of this book.